(A) Field of the Invention
The present invention relates to a probing apparatus for semiconductor devices, and more particularly, to a probing apparatus for semiconductor devices using pressurized fluid to control the temperature uniformity of the platen with objects positioned thereon.
(B) Description of the Related Art
Generally, it is necessary to test the electrical characteristics of integrated circuit devices at the wafer level to check whether the integrated circuit device satisfies the product specification. Integrated circuit devices with electrical characteristics satisfying the specification are selected for the subsequent packaging process, and the other devices are discarded to avoid additional packaging cost. Test time and cost are much increased with the increasing test requirements and conditions especially increasing temperature ranges. The time required for the test system to be stabilized increases with increasing temperature and larger wafer size. The cause is result of requiring test electronics, probe station, probe units and probes to stable at the test temperature.
To initiate the electrical testing, the integrated circuit device is positioned on a device holder with temperature-controlling unit, which adjusts the temperature of the device under test according to the predetermined testing temperature. This testing is not conducted until the temperature of the testing environment is stable. Unstable test environment will result in probe movement on the contacting area of the device under test and the probe may moved out of the contacting areas (probe pads). To probe different devices during the electrical testing, the device holder has to move the wafer under test such that the probe of the probe card can contact different integrated circuit devices or different pads of the same integrated circuit device. However, the location of the device holder under higher temperature may cause the temperature distribution of the testing environment, leading to the physical dimension changes of the surrounding parts such as the platen, the probe card, or the probes. The physical dimension changes can be the deformation of the surrounding objects due to localized thermal expansion of heated parts and shrinkage of cooler parts. This alters the relative positions of the probes against the contact area on the wafer, which precludes further electrical testing if the probes are not in contact with the contacting areas. Consequently, after the movement of the device holder, the electrical testing cannot be performed until the temperature of the testing environment is stable and the probe are re-aligned to make contact with the contacting areas again so as to ensure the accuracy of the testing result. However, waiting for the testing environment to reach the stable status again consumes time and increases the testing cost.
U.S. Pat. No. 4,820,976, U.S. Pat. No. 6,468,098 and U.S. Pat. No. 6,906,543 disclose probe cards equipped with temperature-adjusting mechanisms, which can only adjust the temperature of the circuit board of the probe card locally, so as to prevent the material of the probe card from undergoing physical dimensional change due to the temperature variation. However, the temperature-adjusting techniques disclosed in these patents cannot prevent the other parts such as the platen or probe unit from physical change due to the temperature variation of the temperature control unit. Changes in test temperature or movement of the wafer will alter the relative positions of the probe against the contacting area such as the probe card and the probe on the platen and the probe pads on the wafer, which precludes further electrical testing.